Filament mounting



1958 A. A. wlsco ETAL 2,848,642

FILAMENT MOUNTING Filed Nov. 19, 1954 United States Patent FILAMENTMOUNTING Alvin A. Wisco, Pompton Lakes, and Stanley L. Sweatt,Belleville, N. J., assignors to Westinghouse Electric Corporation, EastPittsburgh, Pa., a corporation of Pennsylvania Application November 19,1954, Serial No. 470,000

3 Claims. (Cl. 313-279) This invention relates to filament mounting andhas particular reference to the mechanical and electrical junctionbetween the filament and its lead-in wires in an electric lamp.

It is present day practice to pre-fabricate lamp filaments in manyinstances by providing a coil with two pulled out sections such that thelength of coil between those sections is of proper length to require therated wattage for the lamp. Beyond the pulled out sections there are endcoils which in the past were slipped onto conductor wires well below theends thereof so said conductor wires protruded therethrough and werebent back or hooked after assembly to keep the end coils from thereafterslipping off of the lead-in wires. The prior art mounting is illustratedin Figs. 4 and 5, and it will be observed that there is uncertainty inthe prior art mounting as to exact location of the end coil andpulledout section with respect to the hook of the lead-in wire. Suchprior art mounting is subject to slippage and sparking due tounavoidable looseness of the coil on the wire. Furthermore, in order toinsert the lead-in wire or its equivalent through the end coil but avoidits insertion into the body coil of the filament, the pulled-out sectionhas to be bent sidewise to dis-align the coils. However, the pulled-outsection is the weaker part of the filament and making the additionalbend mentioned and then bending it back again after the lead-in wire orits equivalent is hooked is highly detrimental and results in manyfilaments breaking during fabrication of the lamp.

According to the present invention the above mentioned and otherdeficiencies of prior art lamps are overcome.

In its broad aspect, the invention proposes improved mounting of afilament on its lead-in wire or other wire conductor.

More specificially, the invention contemplates a fixed attachment of thefilament which prevents it from sliding on the conductor wire.

In conjunction with the foregoing, the invention im proves upon andobtains good electrical continuity from the lead-in wire to the filamentin a simple and readily applied manner.

An important objective is to provide for mounting and fixing thefilament on the conductor wire without having to deform the pulled-outsection of the filament.

Other objects, advantages and novel features of construction and methodsteps will appear to persons skilled in the art to which the inventionappertains as the description proceeds, both by direct recitationthereof and by inference from the context.

Referring to the accompanying drawing, in which like numerals ofreference indicate similar parts throughout the several views;

Figure l is a perspective view of a stem assembly which includes ourinvention as part thereof;

Figure 2 is an enlarged sectional View in the plane of ice the conductorwire and associated portion of the filament;

Figure 3 is an elevation of the filament-receiving end of the conductorwire in its initial condition and showing a filament applied thereto;and

Figures 4 and 5 are elevational views showing the prior art mode ofmounting filaments on conductor wires.

As one use and embodiment of the invention, the same is shown in thedrawing as incorporated in an arbitrarily selected type of electric lampstem assembly, but it is to be understood that the invention is likewiseapplicable to other stem assemblies. The stem assembly shown, comprisesa glass flare tube 10 at the upper end of which is a press 11 and withinwhich is a tubulation 12 which has an opening 13 to the exterior of thetube, and interior of the lamp, at the lower end of the press. At theupper end of the press there projects a glass rod 14 coaxial with theflare tube, said rod having a metal tube 15 applied thereover inrelatively tight contact therewith for maintaining substantially axialalignment. The tube extends considerably above the glass rod and at itsupper end receives and retains another glass rod 16 which is beaded atits outer end with the under side of the bead 17 resting on the end ofsaid metal tube. The outer end of said bead is preferably flat, and adisc spacer 18 of insulative material lies across the same and isapproximately centered coaxial with said bead and rod. .Sup-. port wires19 have ends thereof individually sealed in and supported by said bead,all radiating therefrom equal distances to proximity to the periphery ofsaid spacer. Said spacer has a plurality of peripheral notches 20, onefor each of said support Wires which bend up through the notches andback onto the upper surface of the disc, as at 21, constituting grippingmeans to seat and hold said disc in place. Radially inwardly of thenotches said Wires bend again to project upwardly away from the disc ina direction approximately perpendicular to the plane thereof. A filament22 is carried by the upper ends of these several support wires some ofwhich have pig-tail loops 23 around the filament for supportingretention of the filament thereby.

Two of said support wires, distinctively designated as 19', are utilizedas conductors and are equivalent to and function as lead-in wires inrelation to the filament. Lead-in wires 24 of the character well knownin the prior art are sealed through press 11. These lead-in wires arehooked and pinched over the two support wires 19' selected as conductorsand thereby a complete electrical circuit is provided for the filament.These lead-in wires keep the beaded rod and metal tube assembled withrespect to each other and upon the rod 14.

An essential feature of the present invention is the means and method ofattaching the filament to said conductors 19. As initially formed, eachsaid conductor wire 19' is bent, as at 25, to provide a substantiallystraight end portion 26 which projects transversely to the upwardlyprojecting portion of said conductor. According to the illustratedexample, said bend 25 is substantially a right angle. The length of saidtransversely-projecting end portion 26 and the length of end coil 27 ofthe filament up to the pulled-out section 23 thereof are madesubstantially equal and said end coil is slipped onto said end portion26 as shown in Fig. 3. By virtue of bend 25 the conductor provides adefinite stop limiting the insertion of the end portion 26 into thecoil. After the coil is in place, said transversely projecting endportion 26 of conductor 19' is bent intermediate of its ends, as at 29,through a substantial angle, as for example a right angle as illustratedin Fig. 3, so that the part of the end coil next to the pulled-outsection will have substantially axial alignment with the main portion ofthefilament 22 next beyond said pulledout section and thereby orientingsaid filament in its position of use in the stem assembly. Thus, it willbe seen that the pulled-out section is not bent during theassemblyandlikelihood of breakage thereat'is reducedonly-locked in place on theconductor 19 but forced into tight engagement and positive electricalcontact therewith. Slippage of the coil is, accordingly, obviatedenabling the length of filament from one conductor to the other to bereadily predetermined and maintained constant for each assembly anduniform for a series of assemblies.

7 We claim: 7

11A filament mounting comprising a wire wound to form a coiled filament,and a conductor having a transversely-projecting end portion which isinserted into and engages a predetermined end section of said coiledfilament, the said end portion of the conductor and engaged filament endsection being bent at a point intermediate of the ends of said conductorend portion through an angle such that said engaged filament end sectionis deformed at said bend and said coiled filament locked in positiveelectrical contact with said conductor.

2. A filament mounting comprising a wire wound to form'a coiledfilament, and a conductor having a transversely-projecting end portionwhich is substantially straight and inserted into the coiled filamentand engages a predetermined end section thereof, the said end portion ofsaid conductorand engaged filament end section being bent at a pointintermediate of the ends of said conductor end portion through an anglesuch that the turns of said filament at said bend are compressed on oneside of the conductor and expanded 'on the opposite side thereof to thuslock the filament on said conductor in positive electrical contacttherewith. i

3. A filament mountingcomprising a wire wound to form a coiled filamenthaving a pulled-out section and an end section, and a conductor having atransverselyprojecting end portion which is inserted into the endsection of said coiled filament, the said end portion of said conductorbeing substantially straight and of such length that it is coextensivewith the said filament end section, said conductor end portion andfilament end section being bent at a point intermediate of their endsthrough an angle such that the spacing between the turns of'said:filament end section at said bend are compressed on one side of theconductor and expanded on the opp osite'side thereof to thus lock saidcoiled filament on said conductor in positive.

electrical contact therewith.

References Cited the file of this patent Lund Mar. 22,1949

